1. Field of the Invention
This invention relates to wire electric-discharge machining (WEDM) technology, and more particularly, to a wire electric-discharge machining apparatus with recycle electric power which is fetched from the snubber circuit of the apparatus and recycled to power the circuit parts that are used for ignition and discharging.
2. Description of Related Art
In a wire electric-discharge machining apparatus, the energy stored in the inductor in the discharging circuit should be drained out after each discharge; otherwise, it could cause damage to the internal circuitry of the apparatus. FIG. 1 is a schematic diagram of a conventional wire electric-discharge machining apparatus. As shown, the apparatus includes a low-voltage ignition circuit 1 having a positive voltage source V3 and a negative voltage source V2; a high-voltage discharging circuit 2 having a negative voltage source V1; and a snubber circuit 3 having a voltage source V4. After each discharge, the excessive energy stored into the inductive part of the discharging path is directed by the snubber circuit 3 to the capacitor C4 and then drained via the switching element SW1 to the ground. If this excessive energy remains in the apparatus and not drained out, it could cause instability to the discharging and also could cause damage to the internal circuit of the apparatus.
One drawback to the foregoing apparatus of FIG. 1, however, is that it would be wasteful in electrical power since the excessive energy is drained out instead of being recycled for use. Moreover, it would be costly to implement this apparatus since the ignition circuit 1 requires two voltage sources to realize.